Lightweight lever for high mechanical stressing

ABSTRACT

The lever is constructed of a hub and a lever arm of composite structure which is secured to the hub. The lever arm is made of one or more strips of resin-impregnated carbon fibers cut from a board of like material. The boards are commercially prepolymerized to a predetermined extent. In addition, a loop of carbon fibers can also be used with the strips to form the lever arm. The arm is secured to the hub by a pressing and curing operation or is secured in place by an overlying cover.

a we MM Miiller 4 July 50, 1974 [54] LIGHTWEIGHT LEVER FOR HIGH2,18%,338 193g hNdoessinsger 133/145 MECHANICAL STRESSING 2,6 ,019 195orris, r. 13 I57 n 2,655,949 /1953 Hagstrom 139/157 Inventor: JochenMuller, Wmterthur. 2,777,472 1/1957 Pfarrwaller 139/145 Switzerland2,990,725 7/l96l King 74/519 3,439,064 4 1969' M k k' 161 205 [731Asslgnee Bmhm 3,551,272 12/1070 161/164 swltlerland 3,762,028 10/1973Swearingen et al 156/306 [22] Filed: May 9, 1973 v PrimaryExaminer-Allan D. Herrmann [21] Appl' 3s8818 Attorney, Agent, orFirm-Kenyon & Kenyon Reilly Carr & Chapin [30] Foreign ApplicationPriority Data May 12, 1972 Switzerland 007030/72 57 ABSTRACT 52 U.S. c174/519, 139/145 139/157 The lever is cwmu-cted hub and a lever arm of156/309 161/196 403/261 composite structure which is secured to the hub.The [5]] Int CL 6058' 9 D0321 49/38 6091-5106 lever armvis made of oneor more strips of resin- 5 Field of Search H 74 519. 1 1/196 213 1 4impregnated carbon fibers cut from 3. board of like 161/205. 156/306 7material. The boards are commercially prepolymer- 7 261 6 ized to apredetermined extent. ln addition, a loop of carbon fibers can also beused with the strips to form [56] References Cited the lever arm. Thearm is secured to the hub by a pressing and curing operation or issecured in place by UNlTED STATES PATENTS an overlying Coven l,0l3,878l/19l2 Hilton 74/548 X 1.902.569 3/1933 McDonald 21 Claims, 6 DrawingFigures OR IN 7 4/519 PATENTEB smamm snmzor 3 PATENTED JUL3 01974 ISHEET BM 5 LIGHTWEIGHT LEVER FOR HIGH MECHANICAL STRESSING Thisinvention relates to a lightweight lever for high In this mechanism, atorsion bar has one end clamped so as not to rotate and the other endclamped to a hub of a picking lever. In addition, a picking stick ispivoted to or in the free end of the picking lever. In order to pick ashuttle, the torsion bar is twisted, and the energy stored in twistingis imparted to the picking lever at un twisting. The picking lever isthus able to act via the picking stick to shoot the shuttle through theshed at a particular speed. Weaving machine performance is determined,inter alia, by shuttle speed and picking rate, and so picking leveraccelerations cannot but be very high. Since shuttle speed is determinedby the energy stored in the torsion bar, the picking lever must be lightto ensure that only some of such energy is consumed in stand heavymechanical stressing. Another advantage is that the lever opens upfurther uses for a number of novel reinforcing fibers such as carbonfibers and boron fibers, which are the starting'materials for novelfiber composites of outstandingly good mechanical properties yet of veryreduced weight. Difficult techniaccelerating the picking lever. Becauseof the high picking rate, the picking lever alos experiences very highalternate impact loads.

Picking levers can, of course, be made from highgrade steel, but arethen heavy. Thus, a relatively large porportion of the torsion energy isconsumed in accelerating the lever.

Accordingly, it is an object of the invention to provide a lever whichis light in weight yet can withstand high mechanical stressing and canbe made cheaply.

It is another object of the invention to provide alever which can beaccelerated by a torsion bar without consuming large amounts of energy.

Briefly, the invention provides a lever having a hub including a pair ofside walls defining a recess and a lever arm of composite structurereceived in the recess. The lever arm is made of at least one Prepregstrip and bears laterally on the side walls of the recess.

In one embodiment, the lever arm has a loop made of composite materialwhich is received in the recess of the hub. in this case, the internalspace of the loop is filled with at least on Prepreg strip; at least oneend face of the loop is covered with at least one Prepregstrip; and theloop, the Prepreg strips and the hub are a secured together to form apressing.

The term Prepreg is used to refer to a strip of material cut from aPrepreg" board which is a board made of resin-impregnated carbon fibers.The boards are commercially prepolymerized to a predetermined extent andare referred to as Prepregs" for short after the word Preimpregnated."

In another embodiment. the lever arm is removably received in the recessof the hub and a cover is removably secured, as by bolts, to the hub tosecure the lever cal problems have to be solved in achieving therequired constructional adaptation of the lever according to theinvention to the special properties and requirements of the novelmaterials. Also, of course, the very high cost of the materials is anobstacle to their further development, since cost has so far restrictedtheir use. A surprising feature is that the cost of the lever accordingto the invention, more particularly, when used as a picking lever inshuttle-type weaving machines, can be considered to be advantageous forindustrial use.

The base of the recess in the lever according to the invention canbeshaped to resemble a tongue which extends between the recess sidewalls in the direction of the lever arm. This feature provides a goodconnection between the hub and the lever arm. The lever can be formedwith a pivot aperture embodied by a ring pressed together with thePrepreg strip and by an apertured disc on at least one side of the loop,so that the lever arm is reduced very little in the pivot aperture zone.

. The pressed-in apertured discs and the ring mean that there issubstantially no weakening of the region around the pivot aperture inthe lever arm.

Alternatively, the pivot aperture can be formed by an aperture in thePrepreg strips at an appropriate place.

Advantageously, the Prepreg strips are cut from a Prepreg board, and arelaminated so that the reinforcing fibers in the various strips areoriented differently from one another, thus increasing the bendingstrength of the lever arm. Also, the strips on the sides of the leverarm can have different lengths, so that lever arm thickness decreasesalong the length of the lever arm. Advantageously, the loop is formed ofresinimpregnated reinforcing fibers, to give a very solid core for thelever arm and a strong connection between the arm and the hub.Preferably, the apertured discs are made of resin-impregnatedreinforcing fibers, such as carbon fibers, wound spirally.

In order to increase the strength of the transition between the hub andthe loop, an adhesive means such as adhesive foils or sheets or the likecan be provided between the hub and the loop.

. The lever of the invention is particularly useful as a picking leverin the picking mechanism of a shuttletype weaving machine.

These and other objects and advantages of the invention will become moreapparent from the following detailed descirption and appended claimstaken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates an exploded view of the elements of I the leveraccording to theinvention;

arm in place. The advantage of this embodiment is that by removal of thecover.

diture of labor and, although light in weight, can with- FIG. 1aillustrates an inverted plan view of the hub of the lever of FIG. I;

FIG. 2 illustrates an alternative form of Prepreg strip;

FIG. 3 illustrates a plan view of the lever; FIG. 4a illustrates anotherembodiment of the lever according to the invention; and. FIG. 4billustrates a front elevation of the lever of FIG. 4a with the coverremoved.

Referring to FIG. 3, a picking lever for shuttletype weaving machinescomprises a hub 1 which is made of steel or some other material andwhich has specially shaped portion 2 to connect the huh I to lever arm3.

Referring to FIG. 1, the hub 1 has a clamping part 4 which cooperateswith pins (not shown) which extend through passages 5 and 6 for clampingto a torsion bar of a picking mechanism. The shaped portion 2 of the hub1 comprises a projecting part 7 having a pair of side walls 11, and 12and a base 9 defining a recess 8. Referring to FIG. 1a, the underside ofthe hub 1 is formed with a loop-shaped or U-shaped groove 10 of a depthsuch that the base 9 is absent in the region of side walls 11, 12 and acentral strip-like portion or tongue 13 remains between the side walls11, 12. A number of Prepreg strips 15-24 which partly resemble the shapeof the finished picking lever shown in FIG. 3 are disposed one aboveanother in laminated fashion on the underside of the lever.

The lengths of the strips 15-24 decrease towards the center of thelayering, then increase away from the center. The difference in lengthleads to a tapering of the thickness of the picking lever in adecreasing manner along its length towards the free end. An apertureddisc is positioned with an outside periphery 34 in abutment with one end25 of strip 24. Two Prepreg strips 31, 32 are disposed on the strip 24and have contoured ends, such as concave ends 33 which abut in matingrelation with the outside periphery 34 of the disc 30.

In addition, an adhesive means such as an adhesive foil or sheet or thelike 35, i.e., an adhesive in foil or strip or similar form whose curingcycle corresponds to the curing cycle of the Prepreg strips, is disposedon the strip 32. The function of the strip 35 is to reduce stresses inthe adhesive layer during curing and during pressing of the lever as aresult of differences between the coefficients of expansion of steel andcarbon fibers.

A loop of a carbon fiber Prepreg is positioned on the strip 32 and foilstrip 35 with the inside periphery 41 of a curvedend portion 42 of theloop 41 coinciding to some extent with the inside periphery 43 of theaperture in the disc 30. The opposite end of the loop 40 is disposed inthe groove 10 (FIG. la) in.the underside of hub 1 and bears laterally onthe recess side walls 11, 12. The center of the curved end portion 42and the center of the disc 30 are aligned with each other on. a straightline 44. An adhesive foil or sheet or the like 45 similar to the firstsuch foil strip 35 is disposed on the loop 40 to lie between the tongue13 and the loop 40.

A ring 46 is disposed in the curved end portion 42 of the loop 40 andthe internal space 47 of the loop 40 is filled up with a number ofPrepreg strips 50-55 having contoured, e.g. concave, ends 56 which abutthe outside periphery 57 of the ring 46 in mating relation. The otherend of the strips 50-55 extends as far as the front edge of the tongue13 of huh I.

The inside space of the loop 40 is also occupied by relatively longPrepreg strips 58-67 whose ends 68 cover the hub tongue 13. The ends ofstrips 58-67 are also concave and are covered by an apertured disc 70whose axis also lies on the straight line 44. The loop 40 is alsocovered by anumber of Prepreg strips -103 in which the first few strips75-77 have concave ends abutting the outside periphery 106 of the discwhile the next strips 78-99 decrease continuously in other than justspecified.

length towards the outside. The difference in length also leads to apressed picking lever whose thickness decreases along the length of thearm towards the free end. For the same purpose, the remaining strips100-103 increase continuously in length.

In order to form the lever, the various components as shown in FIG. 1are placed together in laminated form. Thereafter, when pressed at anappropriate pressure and temperature and for an appropriate time, allthe components become integral together to form a pressing, due to theresins flowing together and being cured.

If the picking lever thickness is not required to decrease along thelever length, the strips 15-24 can be of the same length as one another,for instance, of the same length as the strip 15. Similar considerationsapply to the strips 70-103, which can in this case, all be of the samelength as the strip 70.

The thickness of the disc 30 corresponds approximately to the totalheight of the strips 15-24. The disc 30 can be wound by a knownapparatus from a carbon fiber filament which has been resin-impregnatedduring winding. Alternatively, the disc 30 can be made of some othermaterial, such as a metal or plastics, as can the disc 70. The ring 46can also be made of a plastics or metal material.

The loop 40 too is wound by a known winder from a carbon fiber filamentresin-impregnated during winding. The loop can also be wound from aPrepreg tape or band or the like.

The Prepreg strips are cut from a Prepreg board using a template so thatthe angle between the grain direction in the board and the longitudinalaxis of the picking lever is alternately 0, 45 and 45 for the Prepregstrips. The grain angle for each Prepreg strip is indicated in FIG. 1 byshort lines. For instance, the angle for the strips 15, 16, 17 is 0,+45and 45, respectively. The grain orientation can, however, be

The number of Prepreg strips 15 24 and IS-I03 is determined by therequired thickness of the finished picking lever. The number of strips50-67 in the interior 47 of the loop 40 is determined by loop height.For example, the strips 50-67 are provided in a number such that, afterpressing, the entire interior of the loop 40 is filled with compositematerial. The strip shape depends upon the shape required for thefinished picking lever, on the shape of the shaped portion 2 in the huband on the shape of the loop 40.

The loop 40 need not necessarily have a covering of Prepreg strips onboth sides. Depending upon strength considerations in the picking lever,it is, of course, possible to have just the strips 15-24 or just thestrips 75-103 on one side.

Referring to FIG. 2, the Prepreg strips can be formed with an aperture107 which serves as the pivot aperture 108 in the finished lever (FIG.3). In this way, the discs 30, 70 can be eliminated. The aperture 108can, of course,- be formed by drilling the lever arm 3 after formation.

Composite materials containing carbon fibers have been mentioned inconnection with the picking lever described, but other compositematerials containing other reinforcing fibers, e.g. boron fibers, can,of course, be considered.

Instead of Prepreg strips, the picking lever can consist of discretecarbon fibers which are introduced into a press, used to make the lever,then impregnated with resin, and then joined together by wet pressing.This applies more particularly to the space 47 inside the loop 40. Thelever can also be made with resinimpregnated whiskers instead of byindividual fibers.

As noted above, the lever is not limited to use as a picking lever ofshuttle-type weaving machines but can by used in other environments.

Referring to FIGS. 40 and 4b, the picking lever can alternativelycomprise a hub 110 formed with a recess 111 having side walls 112, 113in which one rounded end 114 of a lever arm is received. As shown inFIG. 4b, the side walls 112, 113 narrow toward the end to confine thematingly contoured arm 15. in addition, a cover 116 is secured by screws130 to the hub 110 to retain the arm 15 in place.

The lever arm 115 is the same thickness over its whole length.Basically, the lever arm 115 is constructed like the lever arm shown inFIGS. 1 and 3. A loop 120 is made of a composite material with aninternal space taken up by Prepreg strips. Laminations of Prepreg stripsare also disposed on both sides 121, 122 of the loop. A pivot aperture123 is formed either by a ring 124 and apertured discs 125 or by the useof apertured Prepreg strips, for instance, of the kind shown in FIG. 2.The lever arm sides 126, 127 (FIG. 4a) abut the recess side walls 112,113, respectively.

The hub 110 is clamped by a clamping part 128 to a torsion bar 129 of apicking mechanism. After the screws 130 have been released, the leverarm 115 can be removed and replaced by another lever arm.

Instead of a lever arm which comprises a loop, a loopless lever arm canbe provided. in this event, the lever consists just of one or morelaminated Prepreg strips.

It is to be noted that the resin which is used in the Prepreg strips isof a nature to effect a good fibre to resin bond and, an integralbonding of the respective strips together and to the hub. An example ofsuch a resin is an epoxy resin.

What is claimed is:

1. A lever of reduced mass for high mechanical stressing having a hubincluding a pair of side walls defining 'a recess,

and

a lever arm received in said recess in bearing engagement with said sidewalls and extending from said hub, said lever arm including a loop ofcomposite material defining an internal space, at least onepreimpregnated strip of material in said space and at least onepreimpregnated strip of material covering one side face of said loop.

2. A lever as set forth in claim 1 wherein said loop and said stripsare'integrally bonded to each other.

3. A lever as set forth in claim 1 wherein said hub includes an integraltongue between said side walls projecting into said space within saidloop.

4. A lever as set forth in claim 1 further having a ring within saidloop at one end of said lever arm and at least one apertured disc on oneside of said loop aligned with said ring to define a pivot aperture.

5. A lever as set forth in claim 4 wherein each strip within said loophas an end contoured to abut said ring in mating relation and whereinsaid strip on said side face of said loop is contoured to abut said discin mating relation.

6. A lever as set forth in claim 4 wherein said disc is formed of woundreinforcing fibers.

7. A lever as set forth in claim 6 wherein said fibers are carbonfibers.

8. A lever as set forth in claim 1 wherein said strips on said side facehas an aperture at one end to define a pivot aperture.

9. A lever as set forth in claim 1 which includes a plurality of saidstrips, each strip having a graining oriented in angular relation to thegraining of an adjacent strip.

10. A lever as set forth in claim 1 which includes a plurality of saidstrips on said side face of said loop, said plurality including stripsof different lengths along said lever arm with the shorter strips beingdisposed be tween the longer of said strips and said loop.

11. A lever as set forth in claim 1 which further includes an adhesivemeans bonding said lever arm to said hub.

12. A lever as set forth in claim 1 1 wherein said adhesive means is anadhesive foil.

13. A lever as set forth in claim 1 wherein said loop is formed of woundreinforcing fibers.

14. A lever as set forth in claim 13 wherein said fibers are carbonfibers.

15. A lever as set forth in claim 1 which further has a cover secured tosaid hub over said lever arm to secure said lever arm in said recess ofsaid hub.

16. A lever as set forth in claim 1 wherein said hub has a clampingportion for securing a bar therein, said clamping portion being disposedin perpendicular relation to said lever arm, and wherein said lever amincludes a plurality of said strips within said loop each having agraining oriented in angular relation to the graining of an adjacentstrip, and a plurality. of said strips on opposite side faces of saidloop each having a graining oriented in angular relation to the grainingof an adjacent strip, at least some of said latter strips being ofdifferent lengths to define a tapered lever arm.

17. A lever of reduced mass for high mechanical stressing having a hubincluding a pair of side walls defining a recess,

a lever arm received in said recess in bearing engagement with said sidewalls and extending from said hub, said lever arm including at least onepreimpregnated strip of material, and

a cover secured to said hub to secure said lever arm in said recess ofsaid hub.

18. A lever of reduced mass for high mechanical stressing having a hubincluding a recess, and

a lever arm secured in said recess, said lever arm including at leastone strip of resin-impregnated carbon fibers and having an aperture atan end remote from said hub.

19. A lever as set forth in claim 18 wherein said lever is integrallybonded to said hub.

20. A lever as set forth in claim 19 which further has an adhesive meansbetween said hub and said lever arm strip for reducing stresses duringcuring between said hub and said lever arm;

21. A lever as set forth in claim 18 wherein said lever arm has a loopat least partially engaged in said recess and wherein said lever furtherhas a cover removably secured to said hub over said recess to removablysecure saidlever arm in said recess of said hub.

1. A lever of reduced mass for high mechanical stressing having a hubincluding a pair of side walls defining a recess, and a lever armreceived in said recess in bearing engagement with said side walls andextending from said hub, said lever arm including a loop of compositematerial defining an internal space, at least one preimpregnated stripof material in said space and at least one preimpregnated strip ofmaterial covering one side face of said loop.
 2. A lever as set forth inclaim 1 wherein said loop and said strips are integrally bonded to eachother.
 3. A lever as set forth in claim 1 wherein said hub includes anintegral tongue between said side walls projecting into said spacewithin said loop.
 4. A lever as set forth in claim 1 further having aring within said loop at one end of said lever arm and at least oneapertured disc on one side of said loop aligned with said ring to definea pivot aperture.
 5. A lever as set forth in claim 4 wherein each stripwithin said loop has an end contoured to abut said ring in matingrelation and wherein said strip on said side face of said loop iscontoured to abut said disc in mating relation.
 6. A lever as set forthin claim 4 wherein said disc is formed of wound reinforcing fibers.
 7. Alever as set forth in claim 6 wherein said fibers are carbon fibers. 8.A lever as set forth in claim 1 wherein said strips on said side facehas an aperture at one end to define a pivot aperture.
 9. A lever as setforth in claim 1 which includes a plurality of said strips, each striphaving a graining oriented in angular relation to the graining of anadjacent strip.
 10. A lever as set forth in claim 1 which includes aplurality of said strips on said side face of said loop, said pluralityincluding strips of different lengths along said lever arm with theshorter strips being disposed between the longer of said strips and saidloop.
 11. A lever as set forth in claim 1 which further includes anadhesive means bonding said lever arm to said hub.
 12. A lever as setforth in claim 11 wherein said adhesive means is an adhesive foil.
 13. Alever as set forth in claim 1 wherein said loop is formed of woundreinforcing fibers.
 14. A lever as set forth in claim 13 wherein saidfibers are carbon fibers.
 15. A lever as set forth in claim 1 whichfurther has a cover secured to said hub over said lever arm to securesaid lever arm in said recess of said hub.
 16. A lever as set forth inclaim 1 wherein said hub has a clamping portion for securing a bartherein, said clamping portion being disposed in perpendicular relationto said lever arm, and wherein said lever arm includes a plurality ofsaid strips within said loop each havinG a graining oriented in angularrelation to the graining of an adjacent strip, and a plurality of saidstrips on opposite side faces of said loop each having a grainingoriented in angular relation to the graining of an adjacent strip, atleast some of said latter strips being of different lengths to define atapered lever arm.
 17. A lever of reduced mass for high mechanicalstressing having a hub including a pair of side walls defining a recess,a lever arm received in said recess in bearing engagement with said sidewalls and extending from said hub, said lever arm including at least onepreimpregnated strip of material, and a cover secured to said hub tosecure said lever arm in said recess of said hub.
 18. A lever of reducedmass for high mechanical stressing having a hub including a recess, anda lever arm secured in said recess, said lever arm including at leastone strip of resin-impregnated carbon fibers and having an aperture atan end remote from said hub.
 19. A lever as set forth in claim 18wherein said lever is integrally bonded to said hub.
 20. A lever as setforth in claim 19 which further has an adhesive means between said huband said lever arm strip for reducing stresses during curing betweensaid hub and said lever arm.
 21. A lever as set forth in claim 18wherein said lever arm has a loop at least partially engaged in saidrecess and wherein said lever further has a cover removably secured tosaid hub over said recess to removably secure said lever arm in saidrecess of said hub.